Purpose

Fused deposition modeling (FDM) draws particular attention due to its ability to fabricate components directly from a CAD data; however, the mechanical properties of the produced pieces are limited. This paper aims to present the experimental aspect of multi-scale damage analysis and fatigue behavior of polylactic acid (PLA) manufactured by FDM. The main purpose of this paper is to analyze the effect of extruder temperature during the process, loading amplitude, and frequency on fatigue behavior.

Design/methodology/approach

Three specific case studies were analyzed and compared with spool material for understanding the effect of bonding formation: single printed filament, two printed filaments and three printed filaments. Specific experiments of quasi-static tensile tests coupled with microstructure observations are performed to multi-scale damage analysis. A strong variation of fatigue strength as a function of the loading amplitude, frequency and extruder temperature is also presented.

Findings

The obtained experimental results show the first observed damage phenomenon corresponds to the inter-layer bonding of the filament interface at the stress value of 40 MPa. For instance, fatigue lifetime clearly depends on the extruder temperature and the loading frequency. Moreover, when the frequency is 80 Hz, the coupling effect of thermal and mechanical fatigue causes self-heating which decreases the fatigue lifetime.

Originality/value

This paper comprises useful data regarding the mechanical behavior and fatigue lifetime of FDM made PLA specimens. In fact, it evaluates the effect of process parameters (extruder temperature) based on the nature of FDM that is classified as a thermally-driven process.

中文翻译：

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熔融沉积建模（FDM）制造的PLA的多尺度损伤分析和疲劳行为

目的

熔融沉积建模（FDM）因其能够直接从CAD数据中制造组件的能力而备受关注。但是，所生产的零件的机械性能是有限的。本文旨在介绍FDM制造的聚乳酸（PLA）的多尺度损伤分析和疲劳行为的实验方面。本文的主要目的是分析过程中挤出机温度，加载幅度和频率对疲劳行为的影响。

设计/方法/方法

分析了三个特定的案例研究，并将其与线轴材料进行比较以了解粘合形成的影响：单根印刷长丝，两根印刷长丝和三根印刷长丝。准静态拉伸试验与微观结构观察相结合的特定实验可以进行多尺度损伤分析。还显示了疲劳强度随负载振幅，频率和挤出机温度的强烈变化。

发现

获得的实验结果表明，在40 MPa的应力值下，首次观察到的损伤现象与长丝界面的层间粘结相对应。例如，疲劳寿命显然取决于挤出机的温度和加载频率。此外，当频率为80 Hz时，热疲劳和机械疲劳的耦合效应会导致自热，从而缩短疲劳寿命。

创意/价值

本文包含有关FDM制PLA试样的机械性能和疲劳寿命的有用数据。实际上，它基于被归类为热驱动过程的FDM的性质来评估过程参数（挤出机温度）的影响。